If the average of 10, k and 30 is 21. What is the value of k?

If the average of 10, k and 30 is 21. What is the value of k?

Explanation

Given the average of 10, k, and 30 is 21:

(10 + k + 30) / 3 = 21

Multiply both sides by 3:

10 + k + 30 = 63

Combine constants:

40 + k = 63

Subtract 40 from both sides:

k = 23